Patent Literature 1 discloses an electric-motor rotor including a yoke, a resin magnet portion formed integrally with the outer periphery of the yoke, a position-detecting magnet provided at one axial end of the resin magnet portion, and seats formed at the axial end of the yoke on the position-detecting magnet side, each of which includes a pair of protruding portions, and an opening formed between the pair of protruding portions, wherein the resin magnet portion is molded from resin magnet supplied from a donut-shaped runner that protrudes axially outward from the axial end surface of the yoke on the position-detecting magnet side, and that is positioned on the inner side of the yoke, and from ribbed runners that extend radially outward from the donut-shaped runner, and each of the ribbed runners uses the opening of the seat as a resin-magnet supply path, and is also integrated with the seat to form a seat portion. It is described in Patent Literature 1 that due to the configuration as described above, improvement in the quality of the seat portion on which the position-detecting magnet is set in place, and the quality of a position-detecting-magnet holding protrusion that holds the outer periphery of the position-detecting magnet is achieved.